A semiconductor device such as an integrated circuit has a plurality of electrodes projecting from a device main body. The semiconductor device of this kind undergoes an electrical test (inspection) with use of an electrical connecting apparatus referred to as a socket. As one of the electrical connecting apparatuses of this kind, there is one described in Patent Literature 1, for example.
Patent Literature 1: Japanese Patent Appln. Public Disclosure No. 2003-123874
An electrical connecting apparatus described in Patent Literature 1 includes a plate-shaped housing 100, a plurality of plate-shaped contacts 102 arranged in parallel in the housing 100, and a bar-like probe holder 104 arranged in the housing 100 so as to extend in the arrangement direction of the contacts 102, as shown in FIGS. 7(A), (B), and (C).
Such a connecting apparatus is attached to a board 106 such as a wiring board by a plurality of screw members penetrating the housing 100 in its thickness direction and screwed in the board 106. The board 106 has a plurality of strip-shaped conductive portions 108 as part of wires of a wiring pattern on the upper surface of an electrical insulating plate member 110.
The housing 100 has a recess 112 extending in a first direction in the horizontal plane and opened downward, a plurality of slits 114 spaced from one another in the first direction and extending in a second direction perpendicular to the first direction in the horizontal plane, and an opening 116 opened upward and downward and communicating at its lower end portion with the upper portions of the slits 114.
Each slit 114 communicates at its one end portion and its other end portion in the longitudinal direction with the recess 112 and the opening 116, respectively, and is opened at least downward.
Each contact 102 extends in an arc inside the slit 114 from within the recess 112, projects at a tip end (that is, a probe tip) 118 into the opening 116, and directs a curved external surface 120 toward the conductive portion 108.
The probe holder 104 is made of a rubber material such as silicon rubber in a columnar shape and is arranged in the recess 112 in a state of abutting on the contacts 102.
The contact 102 abuts at part of the arc-like external surface 120 on the upper surface of the conductive portion 108 and abuts at its back end surface 122 on a backside inward surface 124 of the recess 112 in a state where the connecting apparatus is attached to the board 106.
When the tip end 118 of each contact 102 and an electrode of a device under test are thrust relatively, an overdrive force OD acts on the contact 102. Accordingly, each contact 102 compresses and elastically deforms the probe holder 104 and angularly rolls on the upper surface of the conductive portion 108 in a state of abutting the curved external surface 120 on the conductive portion 108.
As a result of the above, each contact 102 scrapes away part of the electrode of the device under test and electrically connects the electrode of the device under test to the conductive portion 108. Under this state, an electrical test of the device under test is performed.
However, in the above electrical connecting apparatus, the relative thrust between the tip end 118 of the contact 102 and the electrode of the device under test causes slip between the tip end 118 and the conductive portion 108, as a result of which the conductive portion 108 is damaged through repeated use.
The above phenomenon is explained in further details as follows.
FIG. 7(A) shows a state where the tip end 118 of the contact 102 and the electrode of the device under test are not thrust relatively. In this state, the back end surface 122 of the contact 102 abuts on the backside inward surface 124 of the recess 112.
When the tip end 118 of the contact 102 and the electrode of the device under test are thrust relatively, the contact 102 angularly rolls over the conductive portion 108 in a state where its back end is upward, as shown in FIG. 7(B). At this time, since the contact 102 presses the probe holder 104 to the tip end side and compressively deforms the probe holder 104 so as to press against the probe holder 104 from the backside to the front side, the back end surface 122 of the contact 102 is distanced by a distance L2 from the backside inward surface 124 of the recess 112.
However, since the probe holder 104 is compressively deformed, the contact 102 moves backward by the distance L2 due to a reactive force along with the compression of the probe holder 104 under a state where the back end surface 122 contacts the backside inward surface 124, as shown in FIG. 7(C).
At the time of the above backward movement, the contact 102 is displaced relative to the conductive portion 108 under a state where the curved external surface 120 contacts the conductive portion 108. Consequently, slip occurs between the curved external surface 120 and the conductive portion 108.
The above slip between the two sides occurs every time the overdrive force OD acts on the contact 102. Thus, through repeated electrical tests, the conductive portion 108 abrades away, and electrical connection between the conductive portion 108 and the contact 102 becomes unstable.